Week 6 Flashcards
What is object recognition?
very rapid, effortless, accurate
What are the different changes on perspective?
Position & size
visible surface
Level of illumination
Shadows
What is representation equal to?
match to objects representation stored in memory
What does perceptual organisation depend on?
Identify edges and uniform regions
figure/ground
fill missing edges and surfaces
What is not critical to recognition?
Colour and texture
What is important for recognition?
Shape
What is information does colour provide?
Identify relevant to object behaviour
What are the restricted 3D shapes called?
Geons
What are Geons?
Viewpoint invariant
What is a structural description ?
representation of goons and their spatial relations
What is the view-based theories?
Encoding objects as they appear from a particular view-point
what is stored representation of using views for recognition?
Unfamiliar views require transformation to match to a stored view
What is the best angle of recognition?
anything within a 40 degree angle of trained viewpoint
What neurones respond differently from different viewpoints?
Inferotemporal cortex
What are the clues from the brain?
they are in the Visual hierarchy
Representation of Shape is richer in ____ than ____ .
V4 , V1
Inferotemporal , V4
Neurones become more selective for :
more complex shapes
What are the two descriptions for inferotemporal representation
set of part and their spatial relations
but also view specific
Whats the combination of recognition in regards to resolution?
Complexity and familiarity
View- based and structural description
what are object decoding methods?
fMRI
What is a grandmother cell
a single cell might respond to one and only one objects or person
What is an example of a Conceptual grandmother cell?
a cell for only one object eg word
Are there grandmother cells in the medial temporal lobe?
there are Sparse coding but they are not grandmother cells
What is sparse coding?
the same percept is represented by smaller neuronal ensembles, the members of which respond in an explicit manner to specific features, objects or concepts
majority of neurones are silent for anyone object
the probiblty of finding one cell that responds only to one person or object is :
very small
each cell responds to how many objects or people?
50-150 objects/people
What is not necessary for visual recognition?
Medial temporal lobe
What is DNN stand for?
Deep neural networks
What does DNN mean?
multiple level neural network that can be trained to recognition objects
What happens overtime with DNN?
the network can recognise new objects perspectives
What does visual agnosia ?
impart in deriving the mean of a visually rested stimulus
What is a visual agnosia example?
can describe but don’t know what it is
What does visual agnosia incorporate?
can recognise objects via other sensory modalities, but has no language impairment
What is Prosopagnosia?
A selective agnosia
What are the levels of recognition?
superordinate - level category
Every - level category
subordinate - level category
What does superordinate - level category involve ?
A more general term for an object
What does every - level category involve?
the first thing that comes to mind when identifying and object
What does subordinate - level category involve?
a specific term for an object.
Acquired prosopagnosia?
Person was able to recognise faces prior to suffering a brain injury
What are lesions?
Generally located in ventral occipitotemporal cortex
how can lesions occur?
Results from unilateral right hemisphere lesions
what is Congenital prosopagnosia ?
failed to develop adequate face recognition skills naturally
What is Congenital prosopagnosia misdiagnosed as?
behavioural problems or autistic tendencies
what is Specialisation modularity?
cells respond selectivity to specific stimulus characterises
What is modularity ?
cells that respond to similar stimulus characteristics
Where are modularity located ?
located in potentially identifiable area of the brain
How are modularity located?
fMRI
Bodies >
faces + houses
Faces >
bodies + houses
Houses >
bodies + faces
What does FFA stand for?
Fusiform Face Area
What is FFA?
a small region found on the inferior (bottom) surface of the temporal lobe
What is subtraction method ?
comparing brain activity: one with and one without the mental process of interest.
The difference between regions activated by the mental process.
